The present invention relates to battery performance indicators and more particularly to a transducer which senses various levels of specific gravity and other conditions of a liquid and converts the measurements into binary signals or step wise analog signals which are fed to an indicator read-out. The device of this invention is especially intended for use in measuring the specific gravity of the electrolyte in an electrical storage battery for estimating the available charge remaining in the battery along with measuring other battery conditions.
The best previously known system of measuring specific gravity in a battery is by measurement of the electrolyte using a float such as a hydrometer. The position of the hydrometer float indicates the specific gravity. Another method uses a plurality of colored balls and the specific gravity is indicated by the color of which balls float. A third system involves inserting fiber optic pipes into a chamber in a battery for transmitting a beam of light using additional fiber optic pipes for identifying the position of a float in the chamber by optical means. Another device uses a single float which carries a magnetic core to change the frequency of an oscillator and an optical interrupted light arrangement, both of which tell when specific gravity gets below a fixed point; this type of indicator requires the float to carry the magnetic core load for frequency change and the light arrangement requires a transparent electrolyte. All of these systems rely on the fact that the electrolyte is transparent and visual means or light are required to determine float level or position.
It is the object of this invention to overcome shortcomings found in the prior art and provide a simple, efficient and compact system for determining the charge condition of a battery, or for an entire bank of batteries, as well as other battery conditions.